Shovel crane boom



, 1941., b. c. JONES 23375439 SHOVEL CRANE BOOM Filed March 2, 1940 jATTORNEYS Patented Apr. 8, 1941 SHOVEL CRANE BOOM Daniel 0. Jones,Milwaukee, Wis., assignor to Koehring Company, Milwaukee, Wis., acorporation Application March 2, 1940, Serial No. 321,966

1 Claim.

This invention has to do with exavating machines of the type commonlyknown as shovel cranes or power shovels, wherein there is employed ashovel boom and dipper means mounted on the boom and operated from thepower plant carried on the body of the crane.

The ordinary operation of cranes of this type contemplates an excavatingmovement of the dipper or shovel member usually involving elevatingaction thereof as it is crowded to do its work, a lateral swinging orsweeping of the dipper and its handle by which it is connected with theboom to bring it to an unloading position over a vehicle or a place onwhich the contents ,of the dipper may be dumped, and a subsequentrestoration of the dipper by reverse operations to bring it back to itsexcavating position. The dipper stick either straddles the supportingboom therefor, or passes between spaced parts of such boom and the usualconstructions. The stick forms a long lever, and the operations of thecrane usually are such that the car or body of the crane turns to swingthe boom and dipper instrumentalities. Considerable momentum of theseparts is created in their movement. The ordinary operation of themachine, furthermore, for eiiiciency, requires rather sudden stopping ofthe boom movement for swinging, this being true both when the dipper isloaded and when it is unloaded. Necessarily, this action of the boom anddipper in the stopping movements creates severe stresses and strainsboth upon the boom supporting means at the point of connection with thecrane body, and upon the dipper stick or handle itself. At times theoperator of the machine accidentally side-swipes a vehicle or bank orother obstacle with the dipper, giving rise to additional severetorsional strains on the boom and on the connections at the foot of theboom.

In Patent No. 1,662,902 and in Patent No. 1,954,- 119, there aredisclosed constructions designed to protect the supporting boom fromtorsional forces tending to rotate the boom about an axis longitudinalof the boom caused by the inertia of the dipper upon sudden starting andstopping of the swinging movement of the dipper and by the dipperstriking substantially rigid bodies during such swinging movement. Theconstructions disclosed in such patents employed various arrangements ofcoil springs for absorbing the shocks and forces to which the supportingboom was sub-- jected and which would otherwise have had a damagingeffect upon the structure of the boom and the connections of the boom tothe swing body.

The present invention relates to an improved modification particularlyadapted for use with a supporting boom 01' unitary welded constructionadapted to house part or the mechanism employed ior imparting thecrowding out and racking in movements to the dipper stick and dipper andto which type of supporting boom the application of the inventiondisclosed in the above mentioned patents would be difficult andcomplicated.

In the present invention, there is employed a substantially rigid andunitary supporting boom of Welded construction. The foot 01' the boom isprovided with a pair of supporting arms and there is employed a novelform or connection for securing the boom to the crane or swing body.This construction provides tor a pivotal movement or the boom forraising and lowering the shovel and rubber pads are provided I'orinsulating the boom with respect to the crane or swing body and forabsorbing the shocks due to forces tending to rotate tne boom about anaxis longitudinally of the boom. The rubber pads operate to resilientlyresist turning movement of the boom about its longitudinal axis withrespect to the swing body to which it is secured.

In the drawing, there is shown a preferred embodiment of the invention.In this showing:

Figure l is a diagrammatic side elevational view of a shovel craneconstructed in accordance with the principles of this invention.

Figure 2 is a fragmentary top plan view of a part of the shovel craneillustrated in Figure 1 and showing the manner in which the supportingboom is connected to the car body.

Figure 3 is a side elevational view of a part of the connection shown inFigure 2, one of the supports by which the boom is connected to the carbody being broken away to show the manner in which the pivot block ismounted in the supporting arm at the foot of the boom.

Figure 4 is a sectional view taken substantially on the line 4--4 ofFigure 2; and

Figure 5 is a partial sectional view taken through the top of one of thepivot blocks illustrating the corrugations formed on one of the facesthereof.

Referring to Figure 1 of the drawing, A designates a swing car or bodysupported by a turntable B mounted on endless tracks C. D designates asupporting boom on which is mounted a dipper stick E carrying a shoveldipper F. The dipper F is hoisted by a hoisting cable G and suitablecrowding out and racking in mechanism is provided for imparting outwardand inward movements to the dipper stick E and the shovel dipper F, in amanner well known in the art.

Since the shovel dipper F in the usual shovel crane construction is ofconsiderable weight and occupies a position spaced from the boom D, itwill be apparent that the inertia of the dipper stick E and shoveldipper F upon sudden starting and stopping of the swinging movement ofthe car body A will subject the boom to heavy torsional strains andforces and will tend to impart a rotating movement to the supportingboom about its longitudinal axis. Continued application of such forcesto the supporting boom will in the course of time have a damaging effectupon the structure of the supporting boom. This is particularly true inthose cases wherein the supporting boom is formed substantially in aunitary piece of welded integral construction adapted to house theracking in and crowding out operating mechanism for the dipper stick. Toprevent damage to the supporting boom from such forces, there isprovided a novel connection for securing the boom to the car body whichwill absorb the shocks of the forces referred to.

As best shown in Figure 2, the foot of the boom D is provided with apair of supporting arms I by which the body of the boom D is connectedto and supported by the swing car body A. Each of the supporting arms Iis provided with an opening 2 in which is mounted pivot blocks 3. Thetop and bottom faces of the pivot blocks 3 are insulated from the topand bottom sides of the openings 2 by rubber pads 4.

Bearing members 5 are provided on the sides of the opening 2 forengagement with the sides of the pivot blocks 3 for holding the pivotblocks 3 in a desired position. The bearing members '5 may either be anintegral part of the sides of the openings 2 or may be shims insertablein the space between the sides of the pivot blocks 3 and the sides ofthe openings 2. The bearing members 5 permit turning movement of theboom D about its longitudinal axis 6 with respect to the car body A. Thesides of the bearing or pivot blocks 3 are provided with oil grooves 1connected by an opening 8 drilled through the body of the pivot blockswith an annular oil groove 9 formed on the interior surface of theopening I extending through the pivot blocks 3. The rubber pads 4operate to resiliently resist turning movement of the boom D about itslongitudinal axis in a manner to be described.

Each of the pivot blocks 2 is secured to the car body A by a pivot pinII journaled in the opening IE]. Each of the pins II is carried by apair of supporting arms I2 rigidly and integrally secured to the carbody A. The pins II are mounted in openings formed in the supportingarms I2 and turning movement of the pins I! is prevented by means of alocking bolt I3 extending through the body of the pins I I and a lug I4formed integrally with one of the supporting arms i2. The constructionpermits pivotal movement of the pivot or bearing blocks 3 and the boom Dabout the axis of the pins I I to provide for raising and lowering ofthe boom with respect to the car body A.

It will be recalled that the arrangement of the pivot blocks 3 andbearing members 5 permits turning movement of the boom D about its1ongitudinal axis 6. Upon the subjection of the boom D to forces fromthe dipper stick E and dipper F tending to rotate the same about itslongitudinal axis 6, the rubber pads 4 will operate to resilientlyresist such turning movement and absorb the forces tending to cause suchturning movement and prevent damage to the boom D by reason of suchforces.

Although the boom D has been described as being resiliently insulatedfrom the bearing blocks 3 by means of the rubber pads 4, it will beunderstood that the bearing blocks 3 could be insulated from the body ofthe swing car A without departing from the principles of this invention.

The top and bottom surfaces of the pivot blocks 3 engageable with therubber pads 4 are corrugated or grooved transversely thereof asillustrated in Figure 5 and as indicated by the dotted lines I5 inFigure 4. The transverse corrugations or grooves operate to hold therubber pads 4 in position with respect to the top and bottom surfaces ofthe bearing blocks 3 upon pivotal movement of the boom D about the axisof its supporting pins II.

The arrangement of the bearings 3 and rubber pads 4 also operate torelieve the boom from shocks due to operation of the crowding out andracking in mechanism. Since the boom D carries the chain and mechanismused for this purpose, operation of such mechanism creates a force whichtends to lift the foot of the boom D or supporting arms I verticallyfrom the position shown in Figure 3. Accordingly, it will be apparentthat the pads 4 cushion the boom from the shocks or forces referred toand incident to the operation of the dipper stick crowding out andracking in mechanism.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States, is:

In apparatus of the class described, a support, a rigid and unitary boomelement having a pair of supporting arms at the base thereof, each ofsaid supporting arms being provided with openings having pivot blocksmounted therein and rubber pads insulating the top and bottom sides ofsaid pivot blocks from said supporting arms, and means connecting saidboom element to said swing body for pivotal raising and loweringmovement with respect thereto comprising pivot pins rigidly secured tosaid swing body and journaled in said pivot blocks, said rubber padsbeing effective to absorb torsional forces tending to rotate said boomelement about a longitudinal axis located substantially at right anglesto its axis of pivotal movement by permitting and resiliently resistingturning movem nt of said boom with respect to said pivot blocks and saidswing body.

DANIEL C. JONES.

